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Newton's law of cooling. In the study of heat transfer, Newton's law of cooling is a physical law which states that the rate of heat loss of a body is directly proportional to the difference in the temperatures between the body and its environment. The law is frequently qualified to include the condition that the temperature difference is small ...
Heat equation. Animated plot of the evolution of the temperature in a square metal plate as predicted by the heat equation. The height and redness indicate the temperature at each point. The initial state has a uniformly hot hoof-shaped region (red) surrounded by uniformly cold region (yellow). As time passes the heat diffuses into the cold region.
Defining equation SI unit Dimension Temperature gradient: No standard symbol K⋅m −1: ΘL −1: Thermal conduction rate, thermal current, thermal/heat flux, thermal power transfer P = / W ML 2 T −3: Thermal intensity I = / W⋅m −2
Pressure as a function of the height above the sea level. There are two equations for computing pressure as a function of height. The first equation is applicable to the atmospheric layers in which the temperature is assumed to vary with altitude at a non null lapse rate of : = [,, ()] ′, The second equation is applicable to the atmospheric layers in which the temperature is assumed not to ...
Clausius–Clapeyron relation. The Clausius–Clapeyron relation, in chemical thermodynamics, specifies the temperature dependence of pressure, most importantly vapor pressure, at a discontinuous phase transition between two phases of matter of a single constituent. It is named after Rudolf Clausius [1] and Benoît Paul Émile Clapeyron. [2]
Le Chatelier's principle. In chemistry, Le Chatelier's principle (pronounced UK: / lə ʃæˈtɛljeɪ / or US: / ˈʃɑːtəljeɪ /), also called Chatelier's principle, Braun–Le Chatelier principle, Le Chatelier–Braun principle or the equilibrium law, [1] is a principle used to predict the effect of a change in conditions on chemical ...
Logarithmic mean temperature difference. In thermal engineering, the logarithmic mean temperature difference (LMTD) is used to determine the temperature driving force for heat transfer in flow systems, most notably in heat exchangers. The LMTD is a logarithmic average of the temperature difference between the hot and cold feeds at each end of ...
Definition. The material derivative is defined for any tensor field y that is macroscopic, with the sense that it depends only on position and time coordinates, y = y(x, t): where ∇y is the covariant derivative of the tensor, and u(x, t) is the flow velocity. Generally the convective derivative of the field u·∇y, the one that contains the ...